A security alarm[1] is a system designed to detect intrusion – unauthorized entry – into a building or

area. Security alarms are used in residential, commercial, industrial, and military properties for

protection against burglary (theft) or property damage, as well as personal protection against

intruders. Car alarms likewise protect vehicles and their contents. Prisons also use security systems

for control ofinmates.

Some alarm systems serve a single purpose of burglary protection; combination systems provide

both fire and intrusion protection. Intrusion alarm systems may also be combined with closed-circuit

television surveillance systems to automatically record the activities of intruders, and may interface

to access control systems for electrically locked doors. Systems range from small, self-contained

noisemakers, to complicated, multi-area systems with computer monitoring and control.